Carbs n stuff

Fast Eddie

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Been a while since I was playing with 650 upwards Triumph twins. When I was, general consensus was that 30mm carbs were only for girls, 32s were popular, as was boring out mk1 carbs to 33.5mm, and guys running mk2s ran all sorts of sizes right up to 38mm.

What's the thinking these days for a fast fun road bike? I can't help thinking that 30mm was probably fine all along!!
 

Fast Eddie

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The “cork” in a Triumph head likely is not a 30mm carb.
Well, that depends which other corks you’ve removed first!

As you’ve already discovered John, the first cork is probably those cigar silencers.

Then what, in a T140 it’s probably the exhaust cam?

I’ve got a pair of Hyde half race cams on the shelf that keeping talking to me, whispering temptations into my gullible ear...
 
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One cork is the large and poorly shaped ports on later T120 heads..Raising the intake port floor and slight enlarging the port roof can add noticable power...
T140 can be improved with an earlier 3134 type exhaust cam and moving the intake cam timing to 100 degrees center line..Certianly something to be gained with a proper exhaust system...Lots of opinions on what that is..
 

xbacksideslider

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Hmmm. What’s the T140’s stock intake cam centerline? And, short of splitting cases, what’s to be gained by adjusting the intake cam’s centerline by itself?
 
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